KR102564876B1 - Coated cutting tool comprising an oxide layer - Google Patents

Abstract

An object to be solved by the present invention is to improve the life of a cutting tool by improving oxidation resistance. The present invention base material; A nitride layer coated on the base material; and an oxide layer coated on the nitride layer.

Description

Coated cutting tool comprising an oxide layer}

The present invention relates to a coated cutting tool comprising an oxide layer.

In general, a cutting tool or end mill must have a higher hardness than the material of the workpiece, excellent wear resistance, and at the same time have adequate toughness to withstand the mechanical impact generated during cutting. Materials such as cemented carbide, cermet, and ceramic are known as materials that satisfy these requirements. If these materials are used as cutting tools, the life of the tool is not long due to problems such as abrasion, so materials such as cemented carbide, cermet, and ceramic It is used as a cutting tool by coating it with base material.

For example, in order to improve tool life, non-oxide ceramic materials such as TiN, TiC, TiCN, etc., which have higher hardness than the base material made of cemented carbide, etc., are used by CVD (chemical vapor deposition) or PVD (physical vapor deposition) method Thus, efforts have been made such as single-layer or multi-layer coating on the surface of the base material. However, in the case of cutting under conditions of high processing speed and high temperature and high pressure, the above non-oxide-based thin film reacts with oxygen and is oxidized, or plastic deformation occurs on the edge of the tool due to heat transfer. there is

Registered Patent No. 10-1563034 (2015.10.19.)

An object to be solved by the present invention is to improve the life of a cutting tool by improving oxidation resistance.

One embodiment of the present invention base material; A nitride layer coated on the base material; and an oxide layer coated on the nitride layer.

The thickness ratio of the nitride layer and the oxide layer may be 1:0.1 to 10.

The oxide layer may include a structural oxide layer; and a functional oxide layer. The functional oxide layer may include one or more layers, and a thickness ratio between the structural oxide layer and the functional oxide layer may be 1:0.1 to 10.

The nitride layer or the oxide layer may be deposited by chemical vapor deposition (CVD) or physical vapor deposition.

The chemical vapor deposition may include atomic layer deposition, and the physical vapor deposition includes arc ion plating, magnetron sputtering, or co-sputtering. can do.

Another embodiment of the present invention is a parent material; and an oxide layer coated on the base material, wherein the oxide layer comprises: a structural oxide layer; and a functional oxide layer, wherein the functional oxide layer is composed of one or more layers, and a thickness ratio of the structural oxide layer to the functional oxide layer is 1:0.1 to 10.

Another embodiment of the present invention is to form a nitride layer on the base material; forming an oxide layer on the nitride layer; And the step of applying heat of 500 ~ 700 ℃; a cutting tool coating method comprising a.

According to one embodiment of the present invention, by depositing an oxide layer on the nitride layer, the oxidation resistance of the cutting tool can be improved, thereby improving the lifespan of the cutting tool.

The present invention can improve the lifespan of a cutting tool by limiting the thickness ratio of the nitride layer and the oxide layer.

In the present invention, the oxide layer is composed of a structural oxide layer and a functional oxide layer, and the functional oxide layer or the structural oxide layer is composed of multiple layers to impart various functions to the oxide layer and improve physical properties of the oxide layer.

According to the present invention, tool life can be improved by improving physical properties of the oxide layer by limiting the thickness ratio of the structural oxide layer and the functional oxide layer constituting the oxide layer.

The present invention can improve the tool life by improving the physical properties of the oxide layer by limiting the elements constituting the oxide layer.

According to another embodiment of the present invention, by depositing an oxide layer on the base material, the oxidation resistance of the cutting tool can be improved, thereby improving the lifespan of the cutting tool.

1 is a view showing an oxide layer formed on a nitride layer according to an embodiment of the present invention.
2 is a view showing an oxide layer including a structural oxide layer and a functional oxide layer according to an embodiment of the present invention.
3 is a diagram illustrating a plurality of functional oxide layers according to one embodiment of the present invention.
4 is a view showing an oxide layer formed by magnetron sputtering or atomic layer deposition according to an embodiment of the present invention.
5 is a view showing an oxide layer formed by co-sputtering or atomic layer deposition according to an embodiment of the present invention.
6 is a view showing an oxide layer formed by subsequent heat treatment after co-sputtering according to an embodiment of the present invention.
7 is a view showing an oxide layer including a structural oxide layer and a functional oxide layer according to another embodiment of the present invention.
8 is an X-ray diffraction analysis result of an oxide film formed on a cutting tool.
9 is a view showing a change in wear amount after cutting of a cutting tool.
10 is a photograph of a cutting edge of a cutting tool after a cutting test.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Like reference numerals have been assigned to like parts throughout the specification.

1 is a view showing an oxide layer formed on a nitride layer according to an embodiment of the present invention. Referring to Figure 1, the coated cutting tool 100 according to an embodiment of the present invention is a base material 110; A nitride layer 120 coated on the base material 110; and an oxide layer 130 coated on the nitride layer 120.

The cutting tool 100 may be a cutting tool for cutting difficult-to-cut materials such as titanium material, and may preferably have an end mill shape. The base material 110 may be a cemented carbide, cermet, steel or high-speed steel, preferably a cemented carbide, and in the present invention, the base material 110 may have an end mill shape.

The nitride layer 120 is to improve the lifespan of the cutting tool 100 through combination with the oxide layer 130, and is deposited on the base material 110, and the thickness of the nitride layer 120 is 0.5 to 0.5 It may be 3 μm, and the nitride layer 120 may be composed of one or more layers.

In addition, the nitride layer 120 is one or more elements selected from the group consisting of aluminum (Al), titanium (Ti), silicon (Si), chromium (Cr), vanadium (V), and tungsten (W), or their It may include a compound, preferably AlTiN, TiSiN, AlCrN, or ALNOVA (adding V or W to an AlCrN base), but is not limited thereto, and further includes an element for improving the physical properties of the nitride layer. can do.

In the present invention, the oxide layer 130 is formed on the nitride layer 120, and improves the oxidation resistance of the cutting tool 100 through the combination with the nitride layer 120 to improve the lifespan.

The oxide layer 130 includes aluminum (Al), hafnium (Hf), zirconium (Zr), silicon (Si), vanadium (V), bismuth (Bi), yttrium (Y), niobium (Nb), zinc (Zn) ), one or more elements selected from the group consisting of chromium (Cr), cerium (Ce), and titanium (Ti), or compounds thereof, but is not limited thereto, and an element for improving physical properties of the oxide layer can include more.

The thickness of the oxide layer may be 0.05 to 5 μm.

In addition, the thickness ratio of the nitride layer 120 and the oxide layer 130 may be 1:0.1 to 10, and the life of the cutting tool 100 may be maximized within the thickness ratio.

2 is a view showing an oxide layer including a structural oxide layer and a functional oxide layer according to an embodiment of the present invention.

In the present invention, the oxide layer 130 is a structural oxide layer 132; and a functional oxide layer 131, the structural oxide layer 132 may have a thickness of 0.1 μm to 3 μm, and the functional oxide layer 131 may have a thickness of 0.05 μm to 2 μm. In addition, the oxide layer 130 may include an oxynitride layer.

The structural oxide layer 132 may have a bandgap of 3 eV or more so that foreign substances do not adhere to the coated cutting tool 100 when the cutting tool 100 is used and additional oxidation does not proceed, and high formation energy ), can exhibit physical properties such as high oxidation resistance and high hardness, and can have a multi-layered structure.

In addition, the structural oxide layer 132 may include one or more elements selected from the group consisting of aluminum (Al), hafnium (Hf), zirconium (Zr), and silicon (Si), or a compound thereof, preferably. It may include Al ₂ O ₃ , HfO ₂ , ZrO ₂ or SiO ₂ , but is not limited thereto, and may further include an element for improving physical properties of the structural oxide layer 132 .

3 is a diagram illustrating a plurality of functional oxide layers according to one embodiment of the present invention.

Referring to FIG. 3, the functional oxide layer 131 is a layer having various functions, and can exhibit effects such as low melting point, low friction, high oxidation resistance, and relaxation of internal stress, and the nitride layer 120 and the The life of the cutting tool 100 may be maximized by improving the bonding strength of the structural oxide layer 132, and the functional oxide layer 131 may be composed of one or more layers.

The functional oxide layer 131 is vanadium (V), bismuth (Bi), yttrium (Y), chromium (Cr), niobium (Nb), silicon (Si), zinc (Zn), cerium (Ce) and titanium ( It may include one or more elements or compounds thereof selected from the group consisting of Ti), but is not limited thereto, and optionally includes elements to exhibit effects such as low melting point, low friction, high oxidation resistance, and relaxation of internal stress. can do.

For example, vanadium, bismuth, etc. may be included to exhibit a low melting point effect, vanadium, titanium, titanium oxynitride, etc. may be included to exhibit a low friction effect, and yttrium, Cerium, etc. may be included, and yttrium, titanium, zirconium, zinc, etc. may be included for internal stress relaxation.

The thickness ratio of the structural oxide layer 132 and the functional oxide layer 131 may be 1:0.1 to 10, and the physical properties of the oxide layer 130 may be maximized at the thickness ratio, and various effects may be obtained. Accordingly, the life of the cutting tool 100 can be improved.

In addition, in the present invention, the structural oxide layer 132 may be located on the functional oxide layer 131, but in order to give various functions to the oxide layer 130, the functional oxide layer may be located on the structural oxide layer (not shown) ), a functional oxide layer and a structural oxide layer may be repeatedly formed (not shown).

In the present invention, the nitride layer 120 or the oxide layer 130 may be deposited by chemical vapor deposition (CVD) or physical vapor deposition.

In the present invention, deposition refers to a method of coating a thin solid film of several micrometers on the surface of an object such as metal or plastic with gaseous metal particles.

The chemical vapor deposition is a method of forming a metal thin film by applying heat or plasma to a gaseous metal source and a gas reacting therewith to form highly reactive radicals and causing a chemical reaction on a high temperature substrate. Physical vapor deposition is a method in which energy applied to a desired metal material is converted into kinetic energy, and the material moves and is deposited on a base material to form a thin film.

In the present invention, the chemical vapor deposition may include atomic layer deposition, and the physical vapor deposition may include arc ion plating, magnetron sputtering, or co-sputtering. ) may be included.

In the present invention, the sputtering refers to a phenomenon in which atoms protrude from the surface when the collision energy is greater than the binding energy of the material surface when ionized atoms are accelerated and collide with a material. It is a method in which particles collide with a metal source and protrude atoms are deposited on the base material.

The nitride layer 120 may be deposited using arc ion plating, magnetron sputtering, or atomic layer deposition, and may be deposited at 25 to 300 °C.

The magnetron sputtering may be DC&RF magnetron sputtering, DC magnetron sputtering is a sputtering method using a direct current power source, and the RF magnetron sputtering is a sputtering method using a high frequency power source.

In the present invention, the oxide layer 130 may be manufactured by chemical vapor deposition (CVD) or physical vapor deposition, preferably arc ion plating, magnetron sputtering ( It can be manufactured through magnetron sputtering, atomic layer deposition, co-sputtering, or heat treatment after co-sputtering, and depending on the manufacturing method, the oxide layer 130 may have a different structure.

Hereinafter, the oxide layer 130 formed according to each manufacturing method will be described in detail.

4 is a view showing an oxide layer formed by magnetron sputtering or atomic layer deposition according to an embodiment of the present invention.

Referring to FIGS. 4A and 4B , when the oxide layer 130 is manufactured through magnetron sputtering or atomic layer deposition, a process temperature may be 25° C. to 400° C.

The structure of the oxide layer 130 formed by magnetron sputtering or atomic layer deposition may be a multi-layer structure in which a structural oxide layer 132 is formed on a functional oxide layer 131, and the structural oxide layer It may have a multilayer structure on which a functional oxide layer is formed (not shown). In addition, the functional oxide layer 131 or the structural oxide layer 132 may be formed in the same manner in the case of a multilayer structure.

The magnetron sputtering may be DC&RF magnetron sputtering, DC magnetron sputtering is a sputtering method using a direct current power source, and the RF magnetron sputtering is a sputtering method using a high frequency power source.

Figure 5 is a view showing an oxide layer formed by co-sputtering or selective atomic layer deposition according to an embodiment of the present invention, Figure 5a is a side view of the oxide layer, 5b is a top view of the oxide layer.

Referring to FIG. 5 , when an oxide layer is manufactured through co-sputtering or selective atomic layer deposition, a process temperature may be 25 to 400° C.

The oxide layer 130 manufactured through the co-sputtering or selective atomic layer deposition may include two or more materials, preferably a functional oxide and a structural oxide.

The functional oxide and the structural oxide may form respective regions in the oxide layer 130 . The weight ratio of the functional oxide and the structural oxide may be 1:0.1 to 10.

The co-sputtering is a method of selectively forming a thin film on a sample by sputtering two or more targets at the same time, and the selective atomic layer deposition is a method of forming a selective thin film in a specific area by performing a pretreatment on a sample surface.

6 is a view showing an oxide layer formed by subsequent heat treatment after co-sputtering according to an embodiment of the present invention. FIG. 6A is a view after a co-sputtering process and FIG. 6B is a view after a heat treatment process.

Referring to FIG. 6 , when co-sputtering is followed by heat treatment to form the oxide layer 130, the co-sputtering process temperature may be 25 to 400° C. The heat treatment temperature may be 400 to 900° C., and the weight ratio of oxygen and nitrogen injected during heat treatment may be 1:0 to 1.

The oxide layer 130 formed by subsequent heat treatment after the co-sputtering may undergo spinodal decomposition to form the oxide layer 130, and may include two or more materials, preferably a functional oxide and a structural oxide. can include

Specifically, two or more materials, preferably a functional oxide and a structural oxide, are formed into an amorphous thin film through co-sputtering. Thereafter, the oxide layer 130 may be formed by separating and crystallizing the functional oxide and the structural oxide through heat treatment. The weight ratio of the functional oxide and the structural oxide may be 1:0.1 to 10.

The structural oxide may be an oxide containing one or more elements selected from the group consisting of aluminum (Al), hafnium (Hf), zirconium (Zr), and silicon (Si), or a compound thereof, but is not limited thereto, and An element for improving physical properties of the oxide layer 130 may be further included. In addition, the functional oxide is from the group consisting of vanadium (V), bismuth (Bi), yttrium (Y), chromium (Cr), niobium (Nb), silicon (Si), zinc (Zn) or titanium (Ti) It may be an oxide containing one or more selected elements or compounds thereof, but is not limited thereto, and may further include an element for improving physical properties of the oxide layer 130 .

7 is a view showing an oxide layer including a structural oxide layer and a functional oxide layer according to another embodiment of the present invention.

Referring to Figure 7, another embodiment of the present invention base material 210; and an oxide layer 220 coated on the base material 210, wherein the oxide layer 220 includes a structural oxide layer 222; and a functional oxide layer 221, wherein the functional oxide layer 221 is composed of one or more layers, and the thickness ratio of the structural oxide layer 222 and the functional oxide layer 221 is 1:0.1 to 10. In the tool 200 , the structural oxide layer 222 or the functional oxide layer 221 may have a multilayer structure.

In addition, in the oxide layer 220, a functional oxide layer 221 may be positioned on the structural oxide layer 222, and a structural oxide layer 222 may be positioned on the functional oxide layer 221, and the functional oxide layer 221 and A structural oxide layer 222 may be repeatedly positioned.

Descriptions of the base material 210 and the oxide layer 220 are the same as those of the base material 110 and the oxide layer 130 described above, and thus will be omitted.

Another embodiment of the present invention is to form a nitride layer 120 on the base material 110; forming an oxide layer 130 on the nitride layer 120; And the step of applying heat of 500 ~ 700 ℃; a cutting tool 100 coating method comprising a.

The step of applying heat is a step for improving the crystallinity and hardness of the oxide layers 130 and 220, and by being heated in the above temperature range, the oxide layers 130 and 220 and the cutting tool 100 of the present invention can exhibit excellent hardness. there is.

Descriptions of the cutting tool 100, the base material 110, the nitride layer 120, and the oxide layers 130 and 220 are the same as those described above and will be omitted below.

Hereinafter, specific embodiments according to the present invention will be described.

Example 1

An aluminum chromium nitride film (AlCrN) to which tungsten was added was formed to a thickness of 3 μm on the surface of an end mill made of tungsten carbide (WC) using an arc ion plating technique. A zirconium oxide film (ZrO ₂ ) was formed to a thickness of 2 μm on the nitride film using a magnetron sputtering technique. Thereafter, a post-heat treatment process was performed at 500 to 700° C. to manufacture a cutting tool.

Example 2

An aluminum chromium nitride film (AlCrN) to which tungsten was added was formed to a thickness of 3 μm on the surface of an end mill made of tungsten carbide (WC) using an arc ion plating technique. A hafnium oxide film (HfO ₂ ) was formed to a thickness of 2 μm on the nitride film using a magnetron sputtering technique. Thereafter, a post-heat treatment process was performed at 500 to 700° C. to manufacture a cutting tool.

Example 3

An aluminum chromium nitride film (AlCrN) to which tungsten was added was formed to a thickness of 3 μm on the surface of an end mill made of tungsten carbide (WC) using an arc ion plating technique. A zirconium oxide film (ZrO ₂ ) and a hafnium oxide film (HfO ₂ ) were formed on the nitride film using a magnetron sputtering technique so that the final thickness of the oxide film was 2 μm. Thereafter, a post-heat treatment process was performed at 500 to 700° C. to manufacture a cutting tool.

Comparative Example 1

A cutting tool was manufactured in the same manner as in Example 1, except that post-heat treatment was not performed in Example 1.

Comparative Example 2

A cutting tool was manufactured in the same manner as in Example 2, except that post-heat treatment was not performed in Example 2.

Comparative Example 3

A cutting tool was manufactured in the same manner as in Example 3, except that post-heat treatment was not performed in Example 3.

Comparative Example 4

A cutting tool was manufactured by forming an aluminum chromium nitride film (AlCrN) to which tungsten was added on the surface of an end mill made of tungsten carbide (WC) to a thickness of 3 μm using an arc ion plating technique.

Process conditions for the oxide films prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

process conditions Deposition power (W) Process temperature (℃) injection gas Gas flow (sccm) Process partial pressure (mTorr) 150 - 400 25 - 400 Ar/O2 below 10 1 - 20

Experimental Example 1

The structural analysis of the oxide film of the cutting tools prepared in Examples 1 and 2 was analyzed through X-ray diffraction analysis, and the results thereof are shown in FIG. 8 . An X-ray diffraction method using Cu-Ka rays operated at 30 kV and 40 mA was used.

8 is an X-ray diffraction analysis result of an oxide film formed on a cutting tool. Referring to FIG. 8 , it can be seen that the hafnium oxide layer grew in a monoclinic phase and the zirconium oxide layer grew in a tetragonal phase.

Experimental Example 2

In order to measure the mechanical properties of the cutting tools prepared in Examples 1 to 3 and Comparative Examples 1 to 3, nano-indentation was performed, and Vickers hardness and elastic modulus were measured according to the following measurement method, The results for this are shown in Table 3 below.

[measurement method]

Vickers Hardness: Value obtained by dividing the indentation force (F) by the area (A) of the indented surface

Elasticity modulus: The elastic modulus (E _IT ) is calculated by Equation 1 below using stiffness (S), projected contact area (A _p ), indentation load (Load, P), and deformation amount (h). derived

[Equation 1]

Equation 1: E _IT =

Stiffness (S) is calculated as the slope value when the maximum indentation load is unloaded from the indentation load (P) displacement curve

Measurement conditions were performed with maximum load (5mN), loading rate (10 mN/min), unloading rate (10mN/min), pause time (0s), and the number of press-ins (10 times).

division Vickers hardness (HV) Modulus of elasticity (Gpa) Example 1 2453 452 Example 2 2220 432 Example 3 2362 516 Comparative Example 1 2423 459 Comparative Example 2 2123 417 Comparative Example 3 2112 411

Referring to Table 3, it can be seen that the case of post-heat treatment (Examples 1 to 3) has improved Vickers hardness compared to the case of no post-heat treatment (Comparative Examples 1 to 3). In addition, the hafnium oxide layer (Example 2) exhibited higher mechanical properties than the zirconium oxide layer (Example 1), and the case in which hafnium and zirconium were used together (Example 3) exhibited the best mechanical properties.

Experimental Example 3

The cutting performance of the cutting tools prepared in Examples 1 to 3 and Comparative Example 4 was always evaluated, and was performed under the following conditions, and the results thereof are shown in FIGS. 9 and 10.

The cutting environment ranges from cutting speed (60-70 m/min), RPM (1000 - 2000 rev./min), feed (855 mm/min), overhang (20-40 mm), and wet cutting (1-40 % concentration). Cutting performance evaluation was performed.

9 is a view showing a change in wear amount of a cutting tool after cutting, and FIG. 10 is a photograph of a cutting edge of a cutting tool after a cutting test.

Referring to FIG. 9, it can be seen that the cutting performance is all improved in the case of including the oxide layer (Examples 1 to 3) compared to the case in which only the nitride layer is present (Comparative Example 4), and when hafnium and zirconium are used together (Examples 1 to 3). Example 3) showed the best cutting performance.

In addition, referring to FIG. 10, the cutting edge was good in the case of including a hafnium oxide layer (Example 2) and in the case of including a hafnium and zirconium oxide layer (Example 3), but in the case of including a zirconium oxide layer (Example 1). And in the case of including only the nitride layer (Comparative Example 4), fine chipping occurred. That is, referring to FIG. 10 , it can be confirmed that the state of the edge part is different according to the type and structure of the oxide layer.

In this way, referring to the experimental example, by forming an oxide layer on the nitride layer, it is possible to improve the oxidation resistance of the cutting tool to improve the life of the cutting tool, and by configuring the oxide layer with a different material, the cutting performance can be improved. can confirm that it can.

In the above, preferred embodiments of the present invention have been described in detail. The description of the present invention is for illustrative purposes, and those skilled in the art will understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Therefore, the scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modifications derived from the meaning, scope and equivalent concepts of the claims are interpreted to be included in the scope of the present invention. It should be.

100: cutting tool 110: base material
120: nitride layer 130: oxide layer
131: functional oxide layer 132: structural oxide layer
200: cutting tool 210: base material
220: oxide layer 221: functional oxide layer
222: structural oxide layer

Claims (7)

Base material made of tungsten carbide (WC);
AlCrN nitride layer coated on the base material; and
a ZrO ₂ oxide layer or a HfO ₂ oxide layer coated on the nitride layer;
As a coated cutting tool comprising a,
The coated cutting tool is a coated cutting tool, characterized in that the heat treatment at 500 ~ 700 ℃ after forming the nitride layer and the oxide layer.
According to claim 1,
Coated cutting tool, characterized in that the thickness ratio of the nitride layer and the oxide layer is 1: 0.1 to 10.
delete According to claim 1,
The nitride layer or the oxide layer is a coated cutting tool, characterized in that deposited by chemical vapor deposition (CVD) or physical vapor deposition (Physical Vapor Deposition).
According to claim 4,
The chemical vapor deposition includes atomic layer deposition, and the physical vapor deposition includes arc ion plating, magnetron sputtering, or co-sputtering. A characterized coated cutting tool.
delete Forming an AlCrN nitride layer on a base material made of tungsten carbide (WC);
forming a ZrO ₂ oxide layer or a HfO ₂ oxide layer on the AlCrN nitride layer; and
Applying heat of 500 to 700 ° C;
Cutting tool coating method comprising a.